Added 6-9-18
Updated 23-12-19
My friend Nate put to me an interesting question. If you are in a scenario where the majority of aircraft have a reasonable degree of radar stealth, what is the point of giving your aircraft beyond visual range air-to-air weapon systems if it is necessary for the launch platform to eyeball the target before engaging?
What use is a “beyond visual range” missile when rules of engagement require targets to be visually identified and verified?
If we are to consider the use of fighter aircraft, it may be productive to look at them in a wider context.
Most modern air forces have relatively small numbers of modern fighter jets.
France has decided its forces need 300 combat jets, with 240 for its air force and 60 for its navy.
The USA has settled on 187 F-22s as sufficient for its needs. While it is claimed production of the F-35 will exceed 2,400 aircraft, only a small fraction of this number is likely to be acquired each fiscal year. The USA was planning to buy 13 F-35s initially, with a further order of 179. Fortunately the USA still has a large number of capable older aircraft such as F-15s, F-16s and F-18s. Most customers for F-35 exports were planning to buy 40 to 120.
Britain currently has six squadrons and a flight of Typhoons and six squadrons of Tornados. The UK wants 138 F-35s but so far plans to buy 48, which suggests a future national strength of about 200 aircraft, subject to the inevitable defence cuts.
Despite the fact that its older fighters are no longer airworthy, the F-X2 trials by Brazil intended to acquire only 36 next generation aircraft, the multi-role Saab Gripen being selected.
India’s M-MRCA fighter contract is for around 126+ aircraft.
For less prosperous and less populous countries their aircraft strengths are likely to be even smaller.
Less aircraft produced increases individual unit cost. Combat aircraft continue to get more sophisticated and correspondingly more expensive. It seems likely that the fighter strength of most air forces in the near future will be between several dozen and a few hundred aircraft.
“Fighter” is something of a misnomer in a modern context. Most modern designs need to be multi-role to justify their purchase price and upkeep. The cost of such aircraft often results in less investment in other aircraft types. The modern combat jet must be capable of a variety of air-combat, reconnaissance and surface-attack missions.
This suggests that in the near future. the manned “fast mover” component of an air force will consist of a relatively modest number of one or two designs of multi-role stealth aircraft.
Used correctly, a little air power can go a long way, however. In “A History of Warfare” Montgomery observes:
“The greatest asset of air power is its flexibility. Within the range limitations of their aircraft, air forces are able without change of base to be switched quickly from one objective to another throughout the area of operations. The whole weight of the available air power can thus be used in selected areas in turn. It follows that control of all available air power, land and sea based, must be centralized, and command exercised through one channel.”
Less, more expensive platforms has three consequences:
The first is that up-to-date warplanes will be out of the price range of many combatants. Richer, First World air forces will often enjoy a considerable overmatch against opposition aircraft.
Secondly, even First World air forces are likely to have less aircraft than they would want and individual loses will be more significant.
Thirdly, potential opponents are more likely to field numerous anti-aircraft systems rather than combat aircraft. In recent years, we have seen relatively unsophisticated combat forces willingly investing in surface-to-air systems to counter First World air-capability.
A similar trend towards increased electronic warfare and counter-measures ability seems likely. Increases in such capability would limit the usefulness of remotely-piloted systems.
What changes in fighter design might the conditions described above produce?
Before you can destroy an enemy, you must locate him. There is little point in using a stealth aircraft if you have an active radar broadcasting a massive “here I am!” signal.
Future fighter aircraft may spend the majority of their time with their radar deactivated. Some authors have posed the idea that it is not worth having the weight and expense of an active radar system if it is seldom switched on. I cannot see the radar system totally disappearing from fighter aircraft but it is possible we will see a trend towards lighter, more compact but less capable on-board systems. Related technologies such as passive radio-wave detection and tighter active beams may see increased use. Fighters may have to rely more on guidance from larger, more capable ground, AWACS and naval systems. In place of the active on-board radar, fighter pilots may rely more on other systems.
To “eyeball” a target you do not have to use the naked eye. Many aircraft now mount high-power visible and infra-red camera systems. These may be complemented by millimetric imaging and active systems such as LIDAR. The nose cone of the future fighter may have large transparent sections behind which are gimbal-mounted sensors.
While “dogfighting” may become less common, visual range combats between aircraft will still occur.
Most current medium or long-range air-to-air missiles use radar guidance, which is of limited use against a stealth aircraft with reduced radar reflectance. Whilst long-range missiles with non-radar terminal guidance are possible, these are of limited use without initial location and verification of the target, which may need to be conducted at visual range.
Shorter engagement ranges will mean a change in weapon selection for future combat aircraft. There is little point in carrying large numbers of medium-range air-to-air missiles (MRAAM) if they can only be used at short-range. One possibility is that future fighters will carry larger numbers of shorter-ranged “dogfight missiles”, many in conformational bays or in tubes especially designed for the carriage of such weapons. These would be “off-boresight” missiles that can be fired towards targets outside the launch aircraft’s frontal arc. There may be some merit in configuring some of these launch tubes to fire their missiles to the rear, rather than forward.
Future AAMs will probably make greater use of thrust vector control (TVC) systems, such as was successfully developed for the British Taildog/SRAAM prototype.
Eliminating large aerodynamic control surfaces makes missiles easier to accommodate in internal bays. Smaller stabilizing surfaces can be designed to pop-out after launch. TVC also offers greater manoeuvrability in the first few meters of flight while the missile is still gaining speed. Taildog/SRAAM could make a 90° turn immediately on launch. One test shot nearly hit the nose of its launch aircraft when it turned too tightly!
Obviously, a modern version would not manoeuvre until a few metres from the launch aircraft.
Whilst an aircraft can reduce its radar signature it is probably not practical to totally eliminate its thermal signature. Engines and electronics produce heat that has to go somewhere and a moving aircraft is subject to air friction. Modern heat-seeking missiles do not need to be aimed at the exhaust plume, they are sensitive enough to distinguish between the temperature difference of the aircraft’s skin and its surroundings. In addition to “all-aspect lock-on”, modern missiles also use imagining infra-red technology to lock on to specific heat patterns and signatures, making them harder to decoy. LIDAR may be used to designate a target for missiles that lock onto its visual/IR image.
The heat-seeking dogfight missile is likely to remain a major weapon for engaging stealth targets but is not without its shortcomings. Water is very good at absorbing infra-red wavelengths so heat-seeking missiles can be evaded by using thick cloud.
Some heat-seeking missiles need to “see” the target to lock-on to it before launch. This requires an internal bay that can extend the missile to an external launch position. Internally carriage is likely to spur the adoption of heat-seeking weapons that can lock-on after launch, initial course to acquire the target being programmed into the missile before firing.
The USSR had a policy of producing dogfight AAMs in both heat-seeking and radar-homing versions. Marconi Electronic Systems created an active millimetric radar small enough to fit the Taildog/SRAAM.
Having an alternative to IR guidance for bad weather conditions would be useful, but it remains to be seen if millimetric radar can be used on stealth targets, even at close dogfight ranges.
Rather than use its onboard weapons against a visible target, a future stealth aircraft may instead “call for fires”, directing long-range weapons or drones launched from surface or airborne platforms. Such a technique can be used to engage air and surface targets. In the anti-to-air role long-range missiles might carry multiple dogfight missiles as submunitions, swarming a target’s defences.
Greater use of short-range dogfight missiles will probably see fighters mounting more appropriate countermeasure systems.
Carlton Mayer has suggested that an automatic grenade launcher, possibly using Ring Aerofoil Grenades (RAG), could be used to deploy flares and other countermeasures for an aircraft. GSh-23 cannon mounted in the tails of Tu-95 Bear bombers were used to fire infrared flares and chaff rounds. The use of a belt or magazine-fed launcher to deploy countermeasures will probably yield increases in capacity. Additional, more traditional multi-tube dispensers will doubtless also be used to utilize smaller spaces elsewhere on the airframe. IRCM jammer, DIRCM and laser-based dazzler countermeasures will probably be used too.
It is worth noting that future missile systems are likely to get smarter and be able to distinguish between a valid target and a falling flare.
The aircraft gun may possibly once more become one of the main air-to-air combat systems. Guns are more practical for destroying smaller targets such as some drones.
Many modern western fighters mount a gatling-mechanism cannon. While such weapons are capable of a high sustained rate-of-fire they are also subject to spin-up time. The first few rounds fired are at a lower rate of fire while the barrel mass overcomes its inertia to spin-up to optimum speed. Unless boosted by an external mechanism, spin-up may be as much as half a second, producing a significant reduction in rounds fired at a target when targeting opportunities may last only a second or so. 
Simpler, lighter weapons such as the Gast-system cannon used on some Russian fighters may in fact offer better performance for the short duration engagements likely to characterize future high-speed air-to-air combat. The only recent Western venture into this field was the 25 x 137mm GE-225 (right).
Increased importance of the gun may see fighters once again mounting multiple cannon with larger ammunition reserves. My personal choice would be two double-barrelled 25mm Gast cannon, each with a rate of fire of around 35 rounds per second.
A concept that I considered in the past was for such guns to have a “semi-flexible” mounting system, allowing them to be elevated and depressed up to 30 degrees. There would also be a limited amount of traverse. The upper and lower surfaces of the wing would have long narrow hatches that opened automatically if the guns are raised or lowered. While mechanically more complicated than a fixed gun, such a system would have allowed a target to be acquired while still “off-boresight”. The ability of the guns to track the target during firing would increases the number of hits likely to be scored. During ground attacks, the depressed guns could fire on a target while the aircraft retains a relatively level flight path. Targeting of the guns could be linked to a “Look and Kill” system that is also used with the high-agility dogfight missiles. If neither gun can acquire the target the firing system would be set to automatically change the aircraft’s attitude to bring a gun to bear. Such a system would have been useful for a dogfighter but on a future aircraft the likely frequency of use probably does not justify the weight penalty. Such a system may be useful for ground-attack aircraft and UCAVs.
Directed energy weapons (DEW) are another possible option, both as defensive and offensive systems. Aiming such weapons off-boresight will be easier than for conventional guns. It is probably unlikely that we will see lasers/DEW on the next generation of fighter aircraft, but they may be practical for larger airborne platforms. A distant laser aircraft, operating alongside an AWACS aircraft, would shoot down missiles directed at scouting fighters.
The gun and guided missile are not the only possible armament options.
The familiar 2.75" FFAR air-to-ground rocket was originally developed as an air-to-air weapon. During the 1950s, some fighters had batteries of launch tubes instead of any gun armament. While such rounds were devastating against slow multi-engine bombers, agile fighters proved more difficult to hit, even if salvoes were fired. Air-to-air rockets fell from fashion in favour of guided missiles.
The chief advantage of the guided missile is, however, that it is guided. If a missile cannot lock-on to its target except possibly at relatively short range using its heat signature, we have to ask does it still offer a significant advantage over an air-to-air rocket? Fighters have gotten even faster since the 1950s but a direct hit is no longer necessary. Multiple flechette warheads have been in service several decades and can be used to fill the approximate location of an enemy aircraft with thousands of high-penetration darts. Suitable flechettes may be hearvier than those currently in common use.
Whether the current 2.75" FFAR will be a suitable delivery system is open to doubt. Before flechette release, the rocket has a velocity of around 725 m/s, which is subsonic. Whether this can be used to engage supersonic targets, even at the shorter-ranges envisioned, needs to be determined.
What may be a better idea is to utilize the airframe and propulsion of the dogfight missiles suggested above and create a variant with a flechette warhead. This would be compatible with weapon bays and tubes already designed to accommodate dogfight missiles. To call this proposed variant “unguided” is actually inaccurate. As a dogfight weapon, it will be useful to have an off-boresight launch capability, and if we have an airframe designed for thrust vector control capability we might as well utilize it.
What this line of thought suggests is a dual-mode dogfight missile with an IR seeker and a flechette warhead. If the missile can achieve lock-on it performs as a conventional dogfight missile that blasts a cone of flechettes into its target when it reaches optimum range. If a target lock cannot be achieved for any reason, the missile is fired on a programmed intercept course and detonated so that its flechettes are likely to intersect the course of the target. A flechette missile would also have ground-attack applications.
For surface-attack missions, the stealth aircraft will have internal bays capable of carrying a variety of air-to-surface weapons equivalent in mass or volume to a pair of 2,000 lb bombs.
Another potentially useful unguided weapon might be termed “Bad Confetti”. Suppose a missile or rocket explodes in the likely path of an enemy aircraft. It releases a large cloud of “something” many times wider than the aircraft. The aircraft cannot avoid passing near the cloud and several cubic metres of the material is sucked into the jet intakes. The engines stutter, cough and die. The aircraft plunges to the ground, the pilot having no choice but to eject. There are a number of possible candidates for this “something”. Whatever is used, it needs to be capable of rapidly forming a large cloud, staying aloft for a useful period of time and interacting adversely with a jet engine. Entanglers, cloggers and reactants have been demonstrated as less-lethal weapons that can clog a vehicle engine. For a ground vehicle these can be defended against with air intake filters but this is not an option for a high-performance jet aircraft.
Some of these agents are fibres that entangle fan blades, others melt and adhere to them, unbalancing the turbine. Some interact with lubricants in the engine. Some variants have been called “grit from hell”.
It is possibly that such materials may be used in combination with more traditional attacks. For example, the space between flechettes or a continuous-rod could be packed with agglutinative materials. Such materials have even greater potential if deployed by larger-capacity missiles, such as those used by some long-range surface-to-air systems.
Aerial mines saw some successful use during the Second World War. Using more modern materials and delivery systems, it is not impossible that they may have a future role.
As the destruction of stealth aircraft becomes more problematic, we may see the genie once more let out of the bottle. From the 1950s to 80s the US Air Force deployed two nuclear air-to-air systems, the 1.5kt Genie unguided rocket and the 250t AIM-26 Nuclear Falcon missile. The possibility of using small nuclear weapons to destroy hard to engage but dangerous airborne targets cannot be discounted as a possibility. Thermobaric warheads may see some use, although air density may limit their use to lower altitudes.
The term “fighter” is used with reservation in the above passages. The aircraft is likely to be multi=role and it is quite feasible that the primary mission of future small stealth aircraft will be ISR or ISTAR rather than direct combat.
I prefer to think of such aircraft as a “stealth scout”. The aircraft’s main role would be to locate airborne or surface targets for stand-off munitions launched from surface or airborne platforms. There is a certain symmetry to this projection.
The earliest fighter aircraft evolved from two-seaters used for reconnaissance and fire-direction. These single-seat fighters were called “scouts”. The stealth scout primarily serves as the local “eyes on the prize” for those with bigger sticks. This approach helps address the problem that future conflicts are likely to have fewer aircraft in theatre than in previous wars. Rather than ASMs or bombs, the “stealth scout” is more likely to carry expendable sensor drones in its weapons bay. While the scout’s role primarily becomes reconnaissance and fire direction, prudence suggests that some armament is retained. It is useful to have some capability to attack targets of opportunity that cannot be engaged by external sources.
The stealth scout is complimented by the use of drone or missile-carrying “arsenal planes” that can engage air or surface targets the scout locates. These missiles may be a family of modular missiles using a common airframe(s), along the lines proposed for the MBDA Flexis concept.
Some arsenal planes will be based a larger variety of stealth aircraft, while some may be based on commercial airliner airframes.
The “large stealth” airframe (a “stealth carrier”) is also likely to be used for other roles. The laser defence and AWACS platforms that were described above supporting the stealth scout may be based on the large stealth airframe. Other variants are likely to include ground surveillance, electronic warfare, transport, aerial refuelling and bomber configurations.
For a stealth scout to direct fires from other systems assumes a functional networking system. This may not be as practical as some planers assume. In recent years, relatively unsophisticated combat forces have willingly invested in surface-to-air systems to counter First World air-capability. A similar trend towards increased electronic warfare and counter-measures ability seems likely.
One countermeasure to such a capability is for the stealth scout to use “tight-bean” line-of-sight transmissions. Such transmissions can be relayed by satellites or high-altitude, long-endurance (HALE) aircraft and airships operating far above the air group.
Stealth aircraft are sophisticated and expensive pieces of equipment and many military missions that occur outside wartime do not in fact need all of their capabilities. One does not use a thoroughbred racehorse to pop down the shops for milk, nor do you use a main-battle-tank to police a sleepy suburb.
In the future the expense of operating and maintaining advanced technology aircraft may justify the adoption of alternate simpler aircraft for the more routine day-to-day operations that will occur outside wartime. See my article on the “Patrol Interceptor” for some thoughts on this platform.
By the Author of the Scrapboard : | |
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 | Attack, Avoid, Survive: Essential Principles of Self Defence Available in Handy A5 and US Trade Formats. |
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 | Crash Combat Fourth Edition Epub edition Fourth Edition. |
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